This report describes the biochemistry and structure of the "natural" prostaglandins, their isomers, analogues and inhibitors. It may be possible to correlate the functions of these compounds with their molecule configuration and to classify their effects accordingly. Should the model configurations presented hold true, the possibilities of manipulating the basic prostaglandin molecule, prostaglandin synthesis, and metabolism, and of developing action-specific inhibitors appear unlimited, as are the pathological and therapeutic implications.